And yeah, he confirmed he took the videos without either girls's consent.

This is what would freak me out the most. Taking sexual videos without obtaining consent is, in my opinion, abusive. To me, the cheating part is much less significant than the idea that someone felt their sexual desires were more important than their partners' rights to privacy and consent over their own bodies.

Personally, I could probably deal with the cheating issues, but it would be difficult to ever trust someone who violated his/her partners in such a way.